Ed Wilson, who has presented, in Consilience, the most eloquent recent defense of this synthesizing preference in his plea for respectful unification of the sciences and humanities, borrows a lovely phrase from the physicist and historian of science Gerald Holton to describe this emphasis upon a grand unification stretching through the “hardest” science of tiny constituents to the crown of the humanities, or from physics through biology to the social sciences, arts, and human ethics:The Ionian Enchantment . . . It means a belief in the unity of the sciences—a conviction, far deeper than a mere working proposition, that the world is orderly and can be explained by a small number of natural laws. Its roots go back to Thales of Miletus, in Ionia, in the sixth century B.C. . . . The Enchantment, growing steadily more sophisticated, has dominated scientific thought. In modern physics its focus has been the unification of all the forces of nature—electroweak, strong, and gravitation—the hoped-for consolidation of theory so tight as to turn the science into a “perfect” system of thought, which by sheer weight of evidence and logic is made resistant to revision. But the spell of the Enchantment extends to other fields of science as well, and in the minds of a few it reaches beyond into the social sciences, and still further, as I will explain later, to touch the humanities.
Wilson does not shy away from granting this traditional dream of unification both its usual direction of subsumption, and its conventional name of “reductionism”: the program of practical research (generally buttressed by a belief, or at least a suspicion, about the actual construction of material reality) that attempts to break the most complex phenomenology (of living, cognitive, and social systems) into constituent units, all ultimately subject to explanation by the unifying physical laws regulating these basic components. Wilson also (pages 58–60) ends his statement by affirming science’s admirable practice of skepticism, with special severity directed at one’s fondest hopes:The cutting edge of science is reductionism, the breaking apart of nature into its natural constituents. The very word, it is true, has a sterile and invasive ring, like scalpel or catheter. Critics of science sometimes portray reductionism as an obsessional disorder, declining toward a terminal stage one writer recently dubbed as “reductive megalomania.” That characterization is an actionable misdiagnosis. Practicing scientists, whose business is to make verifiable discoveries, view reductionism in an entirely different way: It is the search strategy employed to find good points of entry into otherwise impenetrably complex systems. Complexity is what interests scientists in the end, not simplicity. Reductionism is the way to understand it. . . .
Behind the mere smashing of aggregates into smaller pieces lies a deeper agenda that also takes the name of reductionism: to fold the laws and principles of each level of organization into those at more general, hence more fundamental levels. Its strong form is total consilience, which holds that nature is organized by simple universal laws of physics to which all other laws and principles can eventually be reduced. This transcendental world view is the light and way for many scientific materialists (I admit to being among them), but it could be wrong. At the least, it is surely an oversimplification. At each level of organization, especially at the living cell level and above, phenomena exist that require new laws and principles, which still cannot be predicted from those at more general levels.
Wilson revives an old word, consilience, invented by the great English philosopher of science William Whewell in 1840 (I shall provide definitions and analyze Wilson’s misunderstandings of Whewell’s intentions on pages 200–215). I regard consilience as a lovely and deserving term that never caught on in the “natural selection” of English vocabulary. The word literally designates the validation of a theory by the “jumping together” of otherwise disparate facts into a unitary explanation. Wilson revives Whewell’s word to describe the most powerful putative result of reductionism’s triumph: the simplification and gathering together of vast ranges of phenomena by their successive subsumption under laws governing constituent parts, right down to the physics of basic constituents. In Wilson’s dream—the full scale of his Ionian Enchantment—this range of consilience, with reductionism as the explanatory guide, will extend from the physics of elementary particles, to biological and social systems, right up and through the greatest traditional divide (science and humanities) into the arts and ethics as well (pages 221–222)—an extension and alteration of “consilience” quite inconsistent with Whewell’s intentions and basic beliefs about relationships between science and other parts of human life.The central idea of the consilience world view is that all tangible phenomena, from the birth of stars to the workings of social institutions, are based on material processes that are ultimately reducible however long and tortuous the sequences, to the laws of physics. . . . The strategy [of reductionism] that works best in these enterprises is the construction of coherent cause-and-effect explanations across levels of organization. Thus the cell biologist looks inward and downward to ensembles of molecules, and the cognitive psychologist to patterns of aggregate nerve cell activity. . . . No compelling reason has ever been offered why the same strategy should not work to unite the natural sciences with the social sciences and humanities. The difference between the two domains is in the magnitude of the problem, not the principles needed for its solution.
In fairness, for I do regard the logical rebuttal of Wilson’s vision as a strong argument for embracing my alternative form of journey toward a conjunction of the sciences and humanities, I do appreciate his chosen central metaphor for consilience and reductionism—for Wilson’s image reverses the usual geometric picture, thereby rebutting one of the worst collateral implications of classical reductionism. In the usual view, we rank the sciences supposedly subject to reduction in a hierarchy of worth, with adamantine physics on top, and squishy subjects like sociology and psychology on clay feet below. (I must also confess a personal aversion to this picture because, as a paleontologist, I may work with literally hard objects, but my profession surely resides near the squishy conceptual terminus of this continuum!) Thus, the littlest with the mostest generality (and mathematics) is best (particle physics), and the biggest, with a maximally confusing amalgam of different things explained by fewest organizing principles (complex ecological systems, for example), is worst.
At least Wilson reverses this imagery with a comparison to the tale of Theseus and the Minotaur, with the center of the labyrinth not as the starting point for all buildups to larger things nearer the periphery, but rather (and in reverse) as the most difficult goal of final accumulation, with a consilient gain added at each turning from the outside in. That is, you begin with basic particle physics as you enter the labyrinth, and then follow a pathway of ever greater complexity until you reach the most difficult problem at the center (also requiring the not inconsiderable task of slaying a nasty anthropophagous creature with a bull’s head once you arrive). Of course, you can never get out (whatever success you enjoy at the center) unless you carefully lay Ariadne’s thread along your path (corresponding to the intellectual process of continuous subsumption in reductionist explanation), and then trace your conquest at the complex center back through all the levels of ever more general analysis, based on ever more basic constituents, until you reach the physics of the periphery.
This striking image, while rejecting the conventional order of worth (after all, Wilson and I both work as evolutionary biologists, and should be equally loath to regard particle physics as a supreme source), also serves Wilson well in permitting him to make the important point, which I loudly applaud, that the reductive process of consilience can proceed equally well and effectively in either direction, and need not start with quarks, leaving Quercus (oak trees) unaddressed until all the levels below fall into place (pages 73–74):Theseus is humanity, the Minotaur our own dangerous irrationality. Near the entrance of the labyrinth of empirical knowledge is physics, comprising one gallery, then a few branching galleries that all searchers undertaking the journey must follow. In the deep i
nterior is a nebula of pathways through the social sciences, humanities, art, and religion. If the thread of connecting causal explanations has been well laid, it is nonetheless possible to follow any pathway quickly in reverse, back through the behavioral sciences to biology, chemistry, and finally physics. . . . To dissect a phenomenon into its elements . . . is consilience by reduction. To reconstitute it, and especially to predict with knowledge gained by reduction how nature assembled it in the first place, is consilience by synthesis. That is the two-step procedure by which natural scientists generally work: top down across two or three levels of organization at a time by analysis, then bottom up across the same levels by synthesis. . . . There is another defining character of consilience: It is far easier to go backward through the branching corridors than to go forward. After segments of explanation have been laid one at a time, one level of organization to the next, to many end points (say, geological formations or species of butterflies) we can choose any thread and reasonably expect to follow it through the branching points of causation all the way back to the laws of physics. But the opposite journey, from physics to end points, is extremely problematic. As the distance away from physics increases, the options allowed by the antecedent disciplines increase exponentially. Each branching point of causal explanation multiplies the forward-bound threads. Biology is almost unimaginably more complex than physics, and the arts equivalently more complex than biology.
I have no desire to engage in the crudest form of pop psychology, or psychobabble, but I have often wondered why the dream of unification (in our horrendously messy, yet so wondrously multifarious world) holds such power over the scholarly mind. I should, of course, begin with the honest (and rather obvious) admission that such senses of puzzlement tend to increase when the puzzled person doesn’t share the belief that seems so patent and potent to so many respected others. I find nothing either viscerally or intellectually appealing in such neatly and symmetrically honed structures with no rough edges or outlying separate islands (even substantial continents) that don’t connect by intimate physical ties (but may well conjoin in more interesting nonphysical or nonlogical senses better expressed by metaphor or by truly different ways of honoring some higher and eminently worthy commonality). After all, I have written this book, and used the fox and hedgehog rather than Ariadne’s labyrinth as its defining image, because I want the sciences and humanities to become the greatest of pals, to recognize a deep kinship and necessary connection in pursuit of human decency and achievement, but to keep their ineluctably different aims and logics separate as they ply their joint projects and learn from each other. Let them be the two musketeers—both for one and one for both—but not the graded stages of a single and grand consilient unity.
Nietzsche’s famous distinction of the Apollonian (critical-rational) from the Dionysian (creative-passionate) aspects of human motivation may help us to understand two extreme bases for powerful attraction to the ideal of unity. Wilson himself claims illumination from the most Apollonian source of this Enchantment, as expressed in the great secular and intellectual movement of the eighteenth century, the Enlightenment—an episode that he continues to regard as an apogee, albeit an ultimate failure (and for a definite reason), of Western confidence in the power of reason to improve our lives by ensuring continual progress, both factually and morally. Wilson writes (page 15):The dream of intellectual unity first came to full flower in the original Enlightenment. . . . A vision of secular knowledge in the service of human rights and human progress, it was the West’s greatest contribution to civilization. It launched the modern era for the whole world; we are all its legatees. Then it failed.
Wilson ascribes the failures of the Enlightenment to two major reasons, one internal and the other external. For the crumbling from within, these great thinkers could not carry out their rationalist program because the science of their day could not reach sufficiently “upward” in its consilience to explain the complex parts of nature most central to the goal of making our social and economic lives more rational and humane—starting from the human brain and moving upward to social organization and history. Of the Marquis de Condorcet (one of my favorite historical characters as well), who maintained his vision of human perfection even as zealots in the most radical phase of the French Revolution (that he had supported so ardently at its hopeful beginnings) hunted him to his death, Wilson writes (page 21): “His serene assurance arose from the conviction that culture is governed by laws as exact as those of physics. We need only understand them, he wrote, to keep humanity on its predestined course to a more perfect social order ruled by science and secular philosophy.”
Wilson also attributes the failure of later movements for intellectual unification, when based on the same rationalist spirit, to a similar inability to explain complex levels (beginning with the human brain) in scientific terms, thereby precluding the incorporation of these essential subjects into the reductionistic consilience. Of logical positivism, the twentieth-century philosophical movement best developed by a group known as the Vienna Circle (at least until Hitler’s policies forced the dispersion—or encompassed the death—of several key Jewish members), Wilson writes (page 69):Logical positivism was the most valiant concerted effort ever mounted by modern philosophers. Its failure, or put more generously, its shortcoming, was caused by ignorance of how the brain works. That is my opinion of the whole story. No one, philosopher or scientist, could explain the physical acts of observation and reasoning in other than highly subjective terms.
For the defeat of the Enlightenment from without, Wilson notes the powerful forces of human mentality and tradition that find secular reason just a bit “bloodless” and that seem to need (and desperately seek) the thrill of visceral oneness, imposed from above by an authoritarian mystery, worthy of worship. Contrasting the Enlightenment’s deistic “take” on religion with more conventional Western views, for example, Wilson writes (page 36):The fatal flaw in deism is thus not rational at all, but emotional. Pure reason is unappealing because it is bloodless. Ceremonies stripped of sacred mystery lose their emotional force, because celebrants need to defer to a higher power in order to consummate their instinct for tribal loyalty. In times of danger and tragedy especially, unreasoning ceremony is everything. There is no substitute for surrender to an infallible and benevolent being, the commitment called salvation. And no substitute for formal recognition of an immortal life force, the leap of faith called transcendence.
And yet Wilson also (and frequently) invokes the opposite, strongly Dionysian and basically Romantic, rationale for unification as well (using Romantic in a historical and technical sense to define the movement, exalting the primacy of powerful feeling and the innate nature of our emotional needs, that, in the late eighteenth and early nineteenth centuries, became so popular among Western literati and intellectuals following their disenchantment with earlier Enlightenment ideals). Wilson usually cites reduction through his consilient chain (back to principles regulating the more successfully established sciences of smaller components) to support particular claims for explaining more-complex systems, from the brain to human society and on to the arts, ethics, and religion.
Nonetheless—and at several crucial points—he seems to slip into the following basically Romantic argument: How can we validate an ethical principle generally not regarded as enmeshed within a consilient chain that could receive factual affirmation by reduction to a more mature science nearer the perimeter of Ariadne’s labyrinth? Wilson seems to locate an alternative form of “objective” validation—and I don’t know what else to call such a claim but “romantic”—in a principle of consonance with evolved preferences of the human mind, as expressed in the resonance of an ethical precept with a strong and innate feeling within our common nature. We may, by cultural tradition based on misunderstanding of our motives and mental processes (or even just to win greater success in compelling obedience), try to validate the ethical principle in religious or other nonlogical and nonscientific terms,
but the “true” basis of conformity with our evolved nature and being remains preeminent, if unaddressed (and even if entirely unappreciated):The empiricist view in contrast, searching for an origin of ethical reasoning that can be objectively studied, reverses the chain of causation. The individual is seen as predisposed biologically to make certain choices. By cultural evolution some of the choices are hardened into precepts, then laws, and if the predisposition or coercion is strong enough, a belief in the command of God or the natural order of the universe. The general empiricist principle takes this form: Strong innate feeling and historical experience cause certain actions to be preferred; we have experienced them, and weighed their consequences, and agree to conform with codes that express them. Let us take an oath upon the codes, invest our personal honor in them, and suffer punishment for their violation. The empiricist view concedes that moral codes are devised to conform to some drives of human nature and to suppress others.
But the last line exposes the evident dilemma: if human experience, based on consonance with our evolved nature, has led us to prefer certain behaviors (subsequently defined as morally correct and embodied in codes of action), then how can ethical systems be validated within the reductionist chain—that is, as part of factually “true” knowledge, albeit of the most complex and difficult systems—if, at the same time, we must admit that these preferences “conform to some drives of human nature” but “suppress others”? Aren’t the preferences that we suppress just as “natural,” and just as factually evolved, as the ones we have favored? How, then, can we choose, unless we step outside the reductionist chain of scientific fact and admit a different kind of basis for moral validation? Presumably, Wilson would argue that the preferred drives can be factually validated at a still higher level of rules for human cultural organization, rather than biological predispositions of the evolved brain.